import GHC.Types.UnresolvedImport

 import GHC.Data.FastString

 import GHC.Data.Maybe      ( expectJust )

 import qualified GHC.Data.Maybe as M

 import GHC.Data.OsPath     ( OsPath, unsafeEncodeUtf )

 import GHC.Unit.Module.Deps

 import qualified GHC.Unit.Home.Graph as HUG

 import GHC.Unit.Module.Stage

 import Data.Either ( partitionEithers, lefts )

 import Data.Map (Map)

     collect :: [UnitState]

                -- ^ The 'UnitState's of the home units from which to traverse

                --   the dependency graph.

                -- ^ A stateful computation that collects offending dependencies

                --   that have not yet been found. It uses its state, which is an

                --   efficent representation of a set of 'GlobalUnitKey's, to

         -> [UnitId]

            -- ^ The 'UnitId's of the units from which to traverse the dependency

            --   graph.

            -- ^ A stateful computation that collects offending dependencies that

            --   have not yet been found. It uses its state, which is an efficent

            --   representation of a set of 'GlobalUnitKey's, to keep track of

             unit_not_found_msg = "Unit not found during closure property check"

           -- | The ABI hash of the current unit.

           unit_abi_hash = unitAbiHash unit_info

         has_been_processed <- gets $ maybe False (Set.member unit_abi_hash) .